Extend the reach of your telephoto lens with this APO Teleconverter 1.4x EX DG from Sigma for Nikon F-mount cameras and lenses. This model will increase the focal length by about 40% while only losing 1 stop of light in the process. It also retains communication between the lens and camera, allowing users to use automatic metering and autofocus. Additionally, this teleconverter has a multi-layer coating that reduces flare and ghosting for sharp, clear imagery.